1. Field of the Invention
An aspect of the present invention relates to a secondary battery.
2. Description of the Related Art
In general, unlike a primary battery that cannot be recharged, a secondary battery can be discharged and recharged multiple times. Secondary batteries are widely employed in high-technology electronic apparatuses such as cellular phones, laptop computers, camcorders, and the like. In particular, the use of a lithium secondary battery having a high energy density per unit weight and a driving voltage of 3.6V, which is three times larger than that of a nickel-cadmium battery and a nickel-hydrogen battery, is becoming increasingly popular as the power source of electronic apparatuses.
In a lithium secondary battery, a lithium-based oxide is used as a first electrode active material and a carbon material is used as a second electrode active material. The lithium secondary battery is manufactured to have various shapes such as a cylindrical shape, a prismatic shape, and a pouch shape.
In general, the lithium secondary battery includes an electrode assembly, a can accommodating the electrode assembly, and a cap assembly coupled with the can. The lithium secondary battery may present a safety hazard due to a fire or explosion caused by external pressure or shock. Therefore, a lithium secondary battery having an improved safety structure is continuously being developed.